Apparatus for the transmission of alarm signals



.July-'7,1953

L. cHAuvEAu APPARATUS FOR TRANSIYSSION OF ALARM SIGNALS originai manaan. 1s, 1941s 2h sheetssnee' 1 Uv f m M w CU l M k My 7,1953 f L.aM-uvm l 2,644,937'

Ppmms Fon .was mummy original ama' am. '13, 194e fishivsht 2 BYA l A A(L41 A )TOR/Vf' y Patented July 7, 1953 APPARATUS FOR THE TRANSMISSION0F ALARM sIGNALs Louis Chauveau, Paris, France, assignor to SocieteFranaise Radio-Electrique, a corporation of` France Original applicationJanuary 13,' 1948,' Serial No.

1,976, now Patent No. 2,533,765, dated December 12, 1950.

Divided and this application August 2, 1950, Serial No. 177,267. yInFrance January 29, 1947 2 Claims. (Cl. S40-345) The purpose served byalarm-selecting apparatus installed in ships is to release an acousticwarning device when the regular alarm signal is received by theradiotelegraphic receiver of the ship. This regular signal is composed`of a series of twelve dashes of fourv seconds duration separated byintervals of one second. The

selector must respond rto three or four consecue tive dashes. y l n Thisregular signal is keyed manually, so, as to be sent out, by the operatorof the shipm distress. Generally, this .Y operator uses as a guide orcheck a clock or Watchv with a secondhand for checking his keying. As aresult,kthe

dashes and spaces actuallytransmitted .are notr so accurate as theyshould be. p

To allow for this inaccuracy, the limits of a correct dash had beentolerated to be 3-5seconds, Whereas spacing could attain 5 seconds time.Thus, there is a large probability of reception of a signal formed byhand more or less correctly.

Recent regulations `have made the abovelimits narrower and at .thepresent time the correct dash must be comprised between 3.5 and 4.5seconds duration and spacing must ,not be'over 1.5 seconds. Becauseof-this accuracy, ythe modern auto-alarm selectors require as a ,conse-yquence, more accurate. keying bythe operator. If one considers thecircumstances of distress, it is obvious that risks of non-reception ofan alarm signal are considerably increased., j y

The purpose of my present invention is toprovide a remedy, to a certainextent, to the aforesaid drawback. It essentially consists in makingreversible the auto-alarm apparatus, i. e.,` in' permitting of usingthem either as reception selectors, Aor automatic transmission keyingsystems.

This application is a division of ymy application' Serial Number 1,976,iiled January 13, 1948 for Selector Apparatus for Alarm Signals,nowiPatent 2,533,765, dated December 412, 1950. v

For indeed, the auto-alarm selectors include all the necessary membersfor controlling spaces and dashes with accuracy; consequently itwillsuffice to adapt them in ak suitable manner so as to make them control akeying relay which actuates the transmitter of the ship in such mannerthat 'the dashes have four seconds duration and spaces one second, theresult being readily Yobtained Within a precision of the order of le ofa second. Under thesefconditions, in any vessel equipped A with anauto-alarm selector provided withthe improvementv in conformity with theinvention, it will be possible,- if need be,

. tov transmit ,thev alarml signal with they utmostr possibleaccuracy.`y I `,The invention is particularly concerned with the adjunctionto'existng auto-alarmgselectors, of `devices v,pemiitting Vof combiningthe various members of the selector in such manner that the duration ofthe complete cycleis of 5 seconds and second. In addition, one mayeventually provide a member Whichstops they system after the transthecontrol ofthe transmission is interrupted during' one second .in thecourse of each cycle;

the"disposition being such, moreover, that the,

transmitter thus controlledtransmits dashes of four `seconds durationseparated by spaces ofv one mission of. twelve dashes of four seconds.

There is hereinafter given, by way. of anonlimitative'example, the'description of an embodiment of my invention adapted to be applied toan apparatusior the transmission of alarm signals, said apparatus beingv,*diagrammatically of the reception lof every dash. This relay,V shownymore particularly in Fig. 2, has a period v of the orderof one second.It controls by way of its lcontact 8 the chain'of relays shown rin Fig.1 at 'T1-AT1 to T4TAT4 in such ymanner thatv when-the durationbf a dashreceived becomes as great as 3.5 seconds, the contact 28 and T4 isclosed and feeds to the Viirst set vof recording relaysv Ei-AEi, which"keeps being energized so long as the alarm signal received is correct.

At the time of the second'dash, the recording is eiected on relaysE2-AE2. At the time of the third dash, relays Es--AEa operate and thealarm warnillg'y devices SNv are set intol action. When 'a dash lastsfor 415 "seconds, thus being 3 incorrect, a relay T is energized by thefifth pendular impulse; then this relay T5 through Contact 3l cuts offthe general power supply of the system, setting the whole apparatus tostandstill.

When relay AT4 works, that is when a correct dash has just beenreceived, the contact 32 supplies a system SIL of slugged relay withcapacitor 33 and resistor 34, the whole having a time constant of 1.5seconds; as a result, at the end of a correct dash, SIL maintains thewhole being supplied so long as silence does not last more than 1.5seconds.

The starting-up of the above system is promoted at the beginning of eachdash by the slugged relay DM, itself controlled by the reception relayRR.

I provide in the circuit a switch I, a starter relay CEM, and a relayRM, which keys the transmitter when it is energized. The relay E1 mustbe fitted with an extra back contact A and relay T5 must be fitted withan extra make contact B. The additional elements are connected to thepreselector comprising the invention as shown in the broken line wiringdiagram of the drawing.

As can be seen, the switch I closes the circuit of the relay CEM. Thelatter carries a changeover contact C which transfers the circuit of DMfrom contact 1 of RR to make it connect by way of contact B of T5; thisrelay CEM is also fitted with a make contact D which short circuits partof the resistance 34. As a result of this short circuiting, the timeconstant of the assembly, relay SIL, condenser 33 and resistance 34, isreduced from 1.5-0.5 seconds. The operation of the apparatus is now asfollows:

supposing that at the instant of closing switch I the relay RR isunenergized, the relays RM and CEM will operate; the latter by itscontact C tends to supply DM; but the contact B of T5 being open, DMremains at rest. The voltage divider 2 is therefore supplied with power,the intermittent contactor I operates, transmits an impulse 0.1 secondafter receiving its starting torque, and the network relays Tr-ATi toT4-AT4 close step by step.

On the fourth impulse of the intermittent contactor, that is to say atime period of 3+0.1=3.1 seconds after the closing of switch I, relay E1operates and the contact of relay RM opens. At the same time the shuntnetwork, SIL condenser 33 and resistance 34, charges up.

At the fifth impulse, relay T5 operates, cuts the general supply(voltage divider 2) and locks on by way of the contact of relay SIL.

The relay T5 by its contact B provides for the energizing of DM whichopens its contact 5. The energizing of relay T5 is assured by thecontact of SIL for a period of 0.5 second, after which, relay SIL andrelay T5 are energized. 0.4 second after the deenergizing of relay SIL,DM drops off, the

l voltage divider is again energized, and the whole cycle of operationsdescribed above is repeated. This condition persists as long as theswitch I is closed.

The synchronously oscillating relay or intermittent contacter I, shownin Fig. 2, is constituted in the following manner: A flywheel 9 mountedon a shaft I0 to which is attached the spiral spring I I constitutes abalance wheel whose period is of the order of l second; that is to sayit makes two half oscillations per second. The shaft is supported in twobearings I2 and I3. In order to promote starting up and to ensure theoscillation of the balance wheel, this wheel carries a magnetic portionI4, which is attracted by the solenoid I5, the circuit of the latterbeing controlled by the contact I6, the latter contact working under theaction of an arm I1 integral with the shaft. The whole is contrived insuch a way that contact I6 is not closed by arm I1 other than when thebalance wheel is displaced in a clockwise direction, contact I6 beingopen when a movement takes place in the other direction. The wheelcarries another arm I8 which controls contact I8 under the sameconditions.

The shaft I0 carries a hanged collar I9 with a rounded notch whichengages the roller 20 carried by lever 2| which rotates about a shaft25. A spring 22 pulls in this lever so that it maintains the balancewheel in its position of rest. The lever 2l can be displaced by thesolenoid 23 so that it frees the balance wheel and allows it to go intoaction.

To obtain a good performance from such an intermittent contactor it isessential that the magnetic portion I4, the solenoid I5 and the contactI6, are in well dened positions in relation with each other.

'I'hey must not therefore be displaced from these positions. On theother hand contact 8 can be displaced ina slot 24. It is thereforepossible to obtain an advance or'retard in relation to the balancemovement by the positioning of the contact which ensures very preciseadjust ment of the measure of duration of a dash, as will be explainedby the following:

This positioning of the moving contact 8 constitutes another feature ofthe invention.

Normally, in balance wheel devices of this kind, the whole is adjustedso that, when at repose, that is to say at the engagement of roller 20,the arm I1 .is a little behind contact I6; the spiral spring I I is thenlightly wound up in such a way that when unlocking takes place, the armI1 under the inuence of the spiral spring makes contact I6, whence animpulse of current travels to the solenoid I5, and the system startsoperating. However, this method of starting-up is precarious, the usefultorque of the balance wheel being very small at the moment ofstarting-up.

Another feature of the invention lies in the association of a balancewheel with a torque relay LAN, these two elements being interconnectedaccording to Fig. l.

'Ihe relay LAN is disposed in such a way as to impart a strong currentimpulse to the solenoid I5 at the moment of unlocking, and up to thetime of the establishment of contact I6; at this moment the relay LANoperates so as to include the contact I6 in the circuit of themaintaining solenoid I5. A resistance 25 allows control over theintensity of the impulses to obtain correct and continuous functioningof the oscillating relay. At the moment of the transmission of a dash,circuit A is switched on with a lag 0.4 second, the unlocking relay 23operates freeing the balance wheel of the oscillating relay; at the sametime the maintaining solenoid I5 is fed by Way of contact 26 of relayLAN which is not yet energized. A strong impulse drags the balance wheelin a clockwise direction until arm I1 closes contact I6; this latterthen feeds relay LAN which closes and locks on by its contact 21.Contact 26 connects the solenoid circuit I5 to the resistance 25 andcontact I5.

It is thus evident that the balance wheel receives a first and strongimpulse, which ensures prompt starting-up and that it maintains its voscillation under the action of suitably regulated impulses transmittedby contact lli.k

At each oscillation contact B'is closed. At the first oscillation itsclosing takes place abouti); second after the commencement l ofoscillation of the balance wheel. It controlsl the circuit of the relaynetwork 'T1-T4 togetherwith thatofthe auxiliaries AT1-ATi in such awaythat one'set of relays is energized at each impulse.

In light of the foregoing, each cycle of the alarm transmitter can besplit up into four periods: one period of 0.1 second, corresponding tothe delay in the transmission of the first impulse by the intermittentcontactor; one period of 4 seconds corresponding to four completeoscillations of the intermittent contactor, a period of 0.5 second ordrop-off-lag of relay SIL, and a period of 0.4 second corresponding tothe lag in droppingoff of relay DM. This gives a total of0.1-}-4-i0.5+0.4:,5 seconds which represents the working cycle of thetransmitter. 1t must be observed that energizing of relay T4 eiTects theenergizing relay of relay Ei, while relay T5 effects the deenergizing ofthe latter.

As a result during the course of each cycle, the

keying relay RM, whose supply is controlled by contact A of relay E1,will be energized for 4 seconds, and will be at rest forl second.Finally, relay RM by way of its contact keys the transmitter.

It can be seen that the apparatus thus constructed ensures the continuedtransmission of 4 second dashes separated by spaces of 1 second.'

Eventually, a twelve contact telephone stepper switch (not shown) may beconnected in parallel with RM, or be controlled by the latter, so thatafter the tenth dash, this stepper breaks the circuit of CEM, therebyterminatingr transmission.

The auto-alarm selecting apparatus which comprises a stabilized,constant speed motor are equally lcapable of being improved by using thedevice of the invention. 'In the case of such apparatus however, it issimpler-to'adjoin them to a cam driven by the motor and arranged so asto directly control the appropriate transmission;

but it can always be of advantage to adjoin them with the device whichis the subject of this invention, so as to permit of stopping the wholesystem after transmission of twelve dashes.

It will be understood that the examples of application which have beengiven hereinabove are in no way limiting, and the invention may apply,totally or partly to various types of autoalarm selectors or any otherlike apparatus within the scope of the appended claims,

What I claim and desire to secure by Letters Patent of the United Statesis as follows:

l` In a device for transmitting radio-telegraphic signals composed of aseries of dashes of a given duration separated from one another byspaces of another determined duration, a di-l rect current power supply,a potentiometer, three electromagnetic relays each having a contactmember, said potentiometer being fed from said power supply through thecontact members of said three different relays, a mechanism withpendular oscillations, means for normally blocking said mechanism, meansfor unblocking said mechanism when the potentiometer is connected to thepower supply, means connected to the potentiometer and adapted to impartto said mechanism a constant oscillation period equal to the spaceduration of said signals and being a submultiple of the dash duration ofsaid signals, a chain of interconnected countingrelays, a line connectedto the potentiometer, adjustable means cooperating with said line andwith the said Vmechanism to connect said line to the relays,said

means, including a member producing one pulse ing relay-andadapted toconnectthe recording relay to the said potentiometer, a relaycontrolling the transmitter operation, means to conl nect said lastmentioned relay to the power supply through a resting contact of therecordingY n relay, means for periodically opening the circuit to saidpotentiometer and power supply, said lastmentioned means including threerelays each having an armature rand coacting contacts respectivelydesignated make-and-break cut-off, silence, and starting relayscontrolling the three aforementioned contacts, and connecting thepotentiometer to one terminal of the power'supply, the two silence andstartingv contacts being mounted in parallel, and connected in serieswith the contacts of the third make-and-break cutoff relays, whichseparates them from the potentiometer, means associated with the silencerelay and with one of the contacts of the last counting relay to actuatethe silence make-contact opening with a given time delay, the beginningo f the delay period coinciding with the opening of the potentiometersupply circuit, means associated with the starting relay, with amake-contactof the cut-off relayfand with the supply circuit of thepotentiometer, which are adapted to tact, means associated with thepotentiometer supply circuit and another contactmember of the lastcounting relay, which are adapted to bring the cut-off relay excitationandthe bef ginning of the self-excitation of the silence ret lay incoincidencewith the pulse immediately following the one-which caused thelast counting relay to be energized, means associated with themake-and-break contact of the cut-off relay and Vwith one of theterminals of. the power supply to hold saidl cut-off relay energizedafter the displacement of itsarmature, which keffects the opening ofsaid supply circuit, and means for causing the sum of the two said delaytimesand of the time-interval between the pendular mechanismunblocking'andfthe first control pulse, to equal the oscillation periodof said pendular mechanism.

2. A device for transmitting radiotelegraphic sigk nals `as set forth inclaim 1, in which said mechanism with pendular oscillations includes adynamically balanced flywheel having a projecting lug thereonV made of anon-magnetic metal and having a vertical shaft, unblocking meanscomprising acam mounted on said shaft and con operating with a leveradapted` to turn about 7 holding line through one of the contacts ofsaid relays, a flexible contact closed by the said lug during theflywheel rotation., and adjustable mea-ns adapted to adjust the angularposition of this lug respectively to the contact in a given position ofthe flywheel.

LOUIS CHAUVEAU.

References Cited in the le of this patent UNITED STATES PATENTS Number

